From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B0E6C001B0 for ; Fri, 11 Aug 2023 13:32:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235734AbjHKNcv (ORCPT ); Fri, 11 Aug 2023 09:32:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233800AbjHKNct (ORCPT ); Fri, 11 Aug 2023 09:32:49 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7728B30D4 for ; Fri, 11 Aug 2023 06:32:48 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9C66E113E; Fri, 11 Aug 2023 06:33:30 -0700 (PDT) Received: from [10.57.1.174] (unknown [10.57.1.174]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8E63A3F6C4; Fri, 11 Aug 2023 06:32:46 -0700 (PDT) Message-ID: <9582503d-6d48-e5e8-6eb0-a170eb0c1150@arm.com> Date: Fri, 11 Aug 2023 14:32:38 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [RESEND PATCH 1/2] iommu/iova: Add check for cpu_rcache in free_iova_rcaches Content-Language: en-GB To: Zhang Zekun , joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org, baolu.lu@linux.intel.com, robh@kernel.org, nicolinc@nvidia.com, john.g.garry@oracle.com, kevin.tian@intel.com References: <20230811130246.42719-1-zhangzekun11@huawei.com> <20230811130246.42719-2-zhangzekun11@huawei.com> From: Robin Murphy In-Reply-To: <20230811130246.42719-2-zhangzekun11@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023-08-11 14:02, Zhang Zekun wrote: > free_iova_rcaches() needs to check if cpu_rcache->loaded and > cpu_rcache->prev is NULL before freeing them. Why? iova_magazine_free() is just kfree(), and kfree(NULL) is perfectly valid, specifically to avoid having to make cleanup paths all fiddly and overcomplicated like this. Thanks, Robin. > Because > iova_domain_init_rcaches() may fail to alloc magazine for > cpu_rcache->loaded and cpu_rcache->prev, but they will be freed > for all cpus. > > Fixes: 32e92d9f6f87 ("iommu/iova: Separate out rcache init") > Signed-off-by: Zhang Zekun > --- > drivers/iommu/iova.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 10b964600948..3c784a28e9ed 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -746,8 +746,12 @@ int iova_domain_init_rcaches(struct iova_domain *iovad) > > spin_lock_init(&cpu_rcache->lock); > cpu_rcache->loaded = iova_magazine_alloc(GFP_KERNEL); > + if (!cpu_rcache->loaded) { > + ret = -ENOMEM; > + goto out_err; > + } > cpu_rcache->prev = iova_magazine_alloc(GFP_KERNEL); > - if (!cpu_rcache->loaded || !cpu_rcache->prev) { > + if (!cpu_rcache->prev) { > ret = -ENOMEM; > goto out_err; > } > @@ -903,7 +907,11 @@ static void free_iova_rcaches(struct iova_domain *iovad) > break; > for_each_possible_cpu(cpu) { > cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu); > + if (!cpu_rcache->loaded) > + break; > iova_magazine_free(cpu_rcache->loaded); > + if (!cpu_rcache->prev) > + break; > iova_magazine_free(cpu_rcache->prev); > } > free_percpu(rcache->cpu_rcaches);